Non-oriented electrical steel sheet and method for manufacturing same

Patent metadata

Field	Value
Publication number	US-12371757-B2
Application number	US-202017630506-A
Country	US
Kind code	B2
Filing date	Apr 28, 2020
Priority date	Jul 31, 2019
Publication date	Jul 29, 2025
Grant date	Jul 29, 2025

Abstract

Provided is a non-oriented electrical steel sheet having excellent adhesion with an insulating coating even if the thickness of the insulating coating is reduced. The non-oriented electrical steel sheet of the present disclosure has an insulating coating on at least one surface of the steel sheet, where the insulating coating has a P-concentrated layer on both a surface side and an interface side with a steel substrate, and a P concentration of the P-concentrated layer is higher than a P concentration in the steel substrate.

First claim

The invention claimed is:

1. A non-oriented electrical steel sheet comprising an insulating coating on at least one surface of the steel sheet, wherein
the insulating coating has a P-concentrated layer on both a surface side and an interface side with a steel substrate,
a P concentration of the P-concentrated layer is higher than a P concentration in the steel substrate,
the steel sheet has a thickness of 0.20 mm or less and a concentration gradient in which a Si concentration decreases from a surface side of the steel sheet toward a center side of the steel sheet, and
difference in the Si concentration between a surface layer of the steel sheet and a center layer of the steel sheet in the concentration gradient is 1.0 mass % to 5.0 mass %.

2. The non-oriented electrical steel sheet according to claim 1 ,
wherein the steel sheet comprises a chemical composition containing, in mass %,
C: less than 0.010%,
Si: 1.5% or more and 10.0% or less,
Al: 0.001% or more and 2.0% or less, and
Mn: 0.005% or more and 1.0% or less, with the balance being Fe and inevitable impurities.

3. The non-oriented electrical steel sheet according to claim 2 , wherein the steel sheet further contains, in mass %,
P: 0.005% or more and 0.20% or less.

4. The non-oriented electrical steel sheet according to claim 2 , wherein the chemical composition further contains, in mass %, at least one selected from the group consisting of
Sn: 0.002% or more and 0.10% or less,
Mo: 0.005% or more and 0.10% or less,
Sb: 0.005% or more and 0.30% or less,
Cu: 0.01% or more and 0.50% or less,
Cr: 0.01% or more and 0.50% or less, and
Ni: 0.010% or more and 1.0% or less.

5. The non-oriented electrical steel sheet according to claim 3 , wherein the chemical composition further contains, in mass %, at least one selected from the group consisting of
Sn: 0.002% or more and 0.10% or less,
Mo: 0.005% or more and 0.10% or less,
Sb: 0.005% or more and 0.30% or less,
Cu: 0.01% or more and 0.50% or less,
Cr: 0.01% or more and 0.50% or less, and
Ni: 0.010% or more and 1.0% or less.

6. The non-oriented electrical steel sheet according to claim 1 , wherein the insulating coating has an Fe-concentrated layer on the interface side with the steel substrate.

7. The non-oriented electrical steel sheet according to claim 1 , wherein the insulating coating is formed from a coating solution containing one part or more by mass of Mg phosphate.

8. The non-oriented electrical steel sheet according to claim 1 , wherein the insulating coating is formed of a component selected from a group consisting of acryl-based resins, acrylic silicon-based resins, fluorine-based resins, chromate, bichromate, borate, silicate, and a mixture thereof.

9. A method for manufacturing the non-oriented electrical steel sheet according to claim 1 , comprising subjecting a slab for the electrical steel sheet to hot rolling, cold rolling, and then final annealing to obtain a final annealed sheet, and forming an insulating coating on a surface of the final annealed sheet, wherein
the cold rolling is performed using a rolling oil containing 1% or more of a phosphoric ester-type emulsifier,
the insulating coating is formed by applying a solution containing one part by mass or more of a phosphoric acid compound, and
a siliconizing treatment is performed after the final annealing, or the final annealing is final annealing that also serves as a siliconizing treatment.

10. A method for manufacturing the non-oriented electrical steel sheet according to claim 1 , comprising subjecting a slab for the electrical steel sheet to hot rolling, cold rolling, and then final annealing to obtain a final annealed sheet, and forming an insulating coating on a surface of the final annealed sheet, wherein
after the cold rolling and before the final annealing, an aqueous solution containing 5 parts by mass or more of a phosphoric acid compound is applied on a surface of the steel sheet that has undergone the cold rolling, and the aqueous solution is dried,
the insulating coating is formed by applying a solution containing one part by mass or more of a phosphoric acid compound, and
a siliconizing treatment is performed after the final annealing, or the final annealing is final annealing that also serves as a siliconizing treatment.

11. A method for manufacturing the non-oriented electrical steel sheet according to claim 1 , comprising subjecting a slab for the electrical steel sheet to hot rolling, cold rolling, and then final annealing to obtain a final annealed sheet, and forming an insulating coating on a surface of the final annealed sheet, wherein
the cold rolling is performed using a rolling oil containing 1% or more of a phosphoric ester-type emulsifier,
after the cold rolling and before the final annealing, an aqueous solution containing 5 parts by mass or more of a phosphoric acid compound is applied on a surface of the steel sheet that has undergone the cold rolling, and the aqueous solution is dried,
the insulating coating is formed by applying a solution containing one part by mass or more of a phosphoric acid compound, and
a siliconizing treatment is performed after the final annealing, or the final annealing is final annealing that also serves as a siliconizing treatment.

12. A method for manufacturing the non-oriented electrical steel sheet according to claim 1 , comprising subjecting a slab for the electrical steel sheet to hot rolling, cold rolling, and then final annealing to obtain a final annealed sheet, and forming an insulating coating on a surface of the final annealed sheet, wherein
the slab contains 0.005 mass % to 0.20 mass % of P, and an annealing temperature in the final annealing is set to 1100° C. or higher,
the insulating coating is formed by applying a solution containing one part by mass or more of a phosphoric acid compound, and
a siliconizing treatment is performed after the final annealing, or the final annealing is final annealing that also serves as a siliconizing treatment.

13. The method according to claim 12 , wherein the cold rolling is performed using a rolling oil containing 1% or more of a phosphoric ester-type emulsifier.

14. The method according to claim 12 , wherein after the cold rolling and before the final annealing, an aqueous solution containing 5 parts by mass or more of a phosphoric acid compound is applied on a surface of the steel sheet that has undergone the cold rolling, and the aqueous solution is dried.

15. The method according to claim 13 , wherein after the cold rolling and before the final annealing, an aqueous solution containing 5 parts by mass or more of a phosphoric acid compound is applied on a surface of the steel sheet that has undergone the cold rolling, and the aqueous solution is dried.

Assignees

• Jfe Steel Corp

Inventors

• YOSHIZAKI Souichiro
• MIYAMOTO Yukino
• Zaizen Yoshiaki
• Senda Kunihiro

Classifications

• C21D8/00

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• Y10T428/12

  All metal or with adjacent metals · CPC title

• H01F1/147

  Alloys characterised by their composition {(treatment thereof for enhancing their electromagnetic properties C21D8/12)} · CPC title

• C23C10/08

  only one element being diffused · CPC title

• C22C2202/02

  Magnetic · CPC title